The cardio guide

Is swimming good exercise, and how do you start?

By GyroscopeUpdated November 15, 20265 sources

Swimming is great exercise. An easy swim counts as brisk activity, laps count as hard (each minute counts as two), and in 80,306 British adults, swimmers had 28% lower risk of death than people who didn’t swim. Start with one length and a short rest, build from there, and lift weights too, because the water holds your weight and your bones notice.

Swimming has two reputations at once. Some people call it the perfect exercise, every muscle, no impact, nothing to hurt. Others think a few lazy lengths and a soak in the hot tub don’t really count. Both are partly right. How much it gives you depends on how hard you swim, and there’s one thing the pool can’t do for you.

How hard is swimming?

It depends almost entirely on you. The CDC puts “recreational swimming” in the moderate group and “swimming laps” in the vigorous group, where each minute counts as two toward your 150. The Compendium of Physical Activities, which measures how hard things are in METs (the energy of an activity against sitting still), shows how wide the range is.

Treading water at an easy effort is 3.5 METs, barely brisk. Slow freestyle laps are 5.8, and a crawl at about 50 yards a minute is 8, well into the hard band. General swimming that isn’t laps sits at 6, right on the line, which is why the talk test is your best guide in the water too. If you could chat between lengths without catching your breath, you’re at moderate. If you need a few breaths at the wall before you can say anything, you’re at hard.

Does swimming help you live longer?

In the biggest study that looked at it, it did as well as almost anything. In 2017, researchers pooled health surveys of 80,306 adults in England and Scotland and compared people who did each kind of sport with people who didn’t, after adjusting for other differences between them. Swimmers had 28% lower risk of dying from any cause over the following years, and 41% lower risk of dying from heart disease.

Only racket sports did better in that study. These are people who chose to swim, so some of the gap may come from who swims, and it’s one study. But there’s nothing in it to suggest swimming is the soft option.

How do you start if you’re out of practice?

Swim in short pieces with rests. Here’s our pacing for a first swim, not a trial protocol: swim one length at an easy pace, rest 30 seconds at the wall, and repeat for 15 minutes. Count how many lengths you did. Next time, try two lengths before each rest, or the same lengths with shorter rests. When you can swim 10 minutes without stopping, you have a base.

A few things make it easier. A kickboard lets you work your legs and catch your breath at the same time. Breaststroke is fine if your freestyle breathing isn’t there yet, and at a recreational pace it’s 5.3 METs, well inside the brisk band. And if you can’t swim a length yet, adult lessons will get you there faster than struggling alone.

What if your joints hurt?

Then the pool is a good place to be. In water you don’t land on anything, so there’s no pounding through your knees, hips or back, and you can keep moving on days when walking hurts. Water aerobics is 5.5 METs in the Compendium, so a class counts toward your brisk minutes. Walking laps in the shallow end is another way in. If the pain is sharp, getting worse or wakes you at night, see a doctor or physical therapist first (who should check with a doctor first?).

A picture from daily life

Think of hauling a heavy suitcase through an airport, then letting it float in the hotel pool. In the water it weighs almost nothing. Your body gets the same deal when you swim. Your joints get a break from your weight while your heart and lungs still do the work of moving you through the water. Your bones get the break too, and that’s the one catch.

Is swimming good for your bones?

It doesn’t do much for them. In 2013, a team reviewed 64 studies of swimmers’ bones. Swimmers generally had lower bone density than people in high-impact sports and about the same as people who didn’t exercise at all. Their bones did turn over faster, which may make them a little tougher, and swimming doesn’t seem to harm bone. But the reviewers concluded it isn’t one of the best sports for building bone, because the water takes away the impact. If swimming is your main exercise, lift weights twice a week as well (how to get stronger bones on strength.guide).

Is it the perfect exercise?

We’d swim if you enjoy it and have a pool you’ll get to, count it as your cardio, and add two short strength sessions for the rest.

What we still don’t know

The survival figures come from one large study of people who chose to swim, so they describe groups and can’t promise anything to one person. The bone reviewers thought swimming might help bone more later in life, but nobody has shown how much, so we’d still lift.